Bicornuate uterus and miscarriages

So I have a bicornuate uterus and have lost 3 pregnancies. My last was at 21 weeks. My dr said most likely it was my uterus , it was at max capacity and that's why I went into early labor.

I know many with this uterus carry full term , my friend did. But I know there are also different severities.

Has anyone not been able to fully carry? I never want to be pregnant again after this last loss. So I'm going to get my tubes tied and we're thinking about surrogacy. My sister has offered to carry for us.